1. Field of the Invention
With reference to the classifications of art established in and by the U.S. Patent and Trademark Office, the present invention is believed to relate to subject matter found in the Class 81 titled "Tools" and Subclass 63 thereunder titled "Wrenches-pivoted pawl."
2. Description of the Prior Art
There are many ratchet wrenches shown in the documents indexed in the above-identified patent class and subclass, and generally they are shown as wrenches contemplated for clockwise and counterclockwise rotation. Ratchet drives for wrenches have been known for almost, if not more than, a century. A ratchet wrench, for example, is shown in U.S. Pat. No. 228,827 to J. A. Mell issued June 15, 1880. There a simple spring-type lever moves a pawl into one of two positions and each position is resiliently maintained. The pawl is moved selectively to allow the ratchet to provide either a clockwise or a counterclockwise motion or drive. A somewhat similar ratchet wrench is shown in U.S. Pat. No. 460,474 to O. Knapp et al. issued Sept. 29, 1981. The pivoted, resilient arm or trip-bar shown in that patent is manipulated to throw a pawl to provide either a clockwise or a counterclockwise driving effect.
In each of the prior art wrenches just cited the lever or arm whereby the selection of clockwise or counterclockwise drive is made is so positioned that it may be thrown for the selection desired without the user of the wrench having to either release his grip on the normal manual grasping portion of the wrench or use a second hand. Said in other words, the wrenches of Mell and Knapp et al. provide one-hand control for directional drive selection. Neither of those wrenches, however, has the capability in any stable sense by being placed in a neutral condition; that is, a condition in which its pawl is held out of engagement with its ratchet wheel or gear entirely and the wrench handle may be swung in either direction without imparting any significant torque to the driving member of head of the wrench, not even that required to overcome a ratchet spring effect.
There are occasions in the use of ratchet wrenches, especially working in confined areas as is often the case around automotive engines, in which screws or bolts are to be started or withdrawn while gripped only lightly by mating female threads. On such occasions or in such circumstances means must be found to prevent back-turning of the bolt or screw being withdrawn or driven while the ratchet wrench is being reset or repositioned in the course of its backswing. If the concerned bolt cannot be grasped independently by the second hand of the operator, or otherwise, it may be reversed in rotation and undesirably threaded either in or out simply on account of being too lightly held in and by the threads surrounding it for the generation of resistive torque sufficient to lift the ratchet pawl of the wrench.
Ratchet wrenches characterized by neutral or free-wheeling capability provided by various particular structures and mechanisms are shown in U.S. Pat. No. 2,376,575 to J. E. Cronan issued May 22, 1945; U.S. Pat. No. 3,677,102 to E. Simonetta issued July 18, 1972; U.S. Pat. No. 4,063,626 to D. F. Solomon issued Dec. 20, 1977, and U.S. Pat. No. 4,128,025 to H. M. Main et al. issued Dec. 5, 1978. In none of those four wrenches, however, is there the capability of one-hand control by which is meant the capability of the wrench being shifted into either clockwise drive, counterclockwise drive or neutral all by the one hand of the operator used for normal gripping and turning of the wrench while that hand is in a normal wrench-gripping position.